This invention relates to an improved apparatus for removing scrap around the die cut lengths in a web of paper or other materials such as foil, thin plastic, or webs of combined layers of these or similar materials. More particularly, this invention relates to a removable scrap control apparatus that is not attached permanently into the die cylinder on which it is used which permits the use of a double cutoff knife on the same die cylinder without having to have permanent holes, slots or other means to accommodate the scrap control apparatus on the die cylinder or anvil cylinder. Another embodiment relates to a scrap control apparatus for use with configured dies.
Paper cutting machines are widely used to straight or contour cut continuous web to desired sizes without any preliminary step of cutting the web into individual blanks. In general, rotary paper cutting machines have two cooperating rollers or cylinders, one which carries the straight knife or contour die, and the other acts as an anvil against which the knife or die bears as the paper is cut. The cutting edge of the knife and the surface of the anvil normally rotate at the same speed, and the paper is cut as the cutting edge of the knife moves into and out of engagement with the anvil surface. The dies are arranged to cut the maximum number of parts from the web, but inevitably areas of scrap material form because of the complexity of the shapes. At some point, some or all of the scrap is separated from the parts and the scrap is then removed from the die cylinder.
In the conventional rotary paper cutting machine, scrap pieces may be removed by suction alone or by the use of supplementary needles or points for spearing the waste pieces in conjunction with suction. Such points on the cylinder require corresponding openings in the anvil cylinder opposite such points. In some instances, these openings may be filled with rubber or similar resilient material, however, such openings interfere with setup of the machine to different formats or different locations for the pattern to be cut. Attention is required to see if the points or needles exactly register with the openings in the anvil cylinder. This creates difficulty in the changing of setup for different formats or even different positions and sizes of openings.
U.S. Pat. No. 3,186,274 describes a mechanism for removing scrap waste which includes resiliently mounted needles or spear points which in their normal position project from the periphery of the cutting cylinder so that they penetrate the scrap and yield on contact with the hard surface of the counter cylinder. The mounted needles or spear points hold the waste material during rotation of the cutting cylinder to a point where the waste material can be removed by suction. The resilient material comprises a spring for pushing the end of the point into the scrap material. The springs have a workable action to support the needles or points for penetration of the scrap, but are sufficiently yieldable to prevent blunting of the points against the hard surface of the die cylinder and to eliminate the necessity of recesses in the hard surface. Upon impaling, the scrap material is kept on the point near the surface of the die cylinder and by operation of a comb or brush and suction, is removed from the tips of the points. However, if the scrap is not elevated to a sufficient extent above the surface of die cylinder for pickup by the comb or brush for suction by vacuum means, there is a likelihood that it will not be removed. Further, there is danger of marking the anvil by the points which are sprung into the scrap pieces by resilient springs. The present invention is directed to overcoming these and other difficulties inherent in the prior art.
In the present invention an apparatus for removing scrap pieces is provided which includes flexible pointed fingers set into the knife holder or die cylinder between cutting knives or configured dies which contact scrap pieces so that they may be impaled by the pointed fingers. These scrap pieces are impinged on the pointed fingers as scrap pieces pass between the fingers and resilient material on the surface of the anvil cylinder before the nip of the cylinders. The resilient material may be cork, rubber or any elastomeric material. With the apparatus of the present invention, both the anvil cylinder and die cylinder are not damaged by the scrap removal device nor are unnecessary amounts of time required for setup of the knife roller and operation. Further, a specific phase relationship, or angular relationship of the cylinders is not necessary because of the absence of the need to register impaling points and specific positions on the opposing cylinder.